Casting of dentures in metal



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CASTING OF DENTURES IN METAL Filed July 30. 1926 Patented June 14, 1927.

p 1,632,712 UNITED STATES PATENT OFFICE.

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CASTING-Oi DENT'lJ'REB IN METAL.

. Application filed July 30, 1826, Serial lilo. 126,068, and in Great Britain August 19, 1925.

This invention relates to improvements in apparatus for casting dental plates made of gold or other metals-and in particular to apparatus of the type wherein metal is melted on an investment containing the fectively deposited therein in very close contact with the surface of the mould.

To this end the invention is directed to providing apparatus which, during the time that the pot or crucible is being swung on the rod, will permit of lateral oscillating movements being imparted to the crucible. It is also an object of the invention to dispense with the counterweight usually applied .in connection with a rotating weight upon a rod; to provide the crucible with very small exit holes for the discharge of the molten metal, and to keep the investment containing the mould at a temperature, up to the moment of casting, close to the melting point of the metal.

. The pot or crucible that it is proposed to use in this machine is according to that described in United States specification forming3-part' of LettersPatent No. 1,534,952. ut in order to fully understand the invention reference is made to the accompany- .ing drawings, in which, I

ig. 1 is a perspective view of the apparatus Fig. 2 shows the gear box inside elevation with turnin handle and attachment to prevent the bandle being moved the wrongway. I

. Flg. 3 1s a (perspective. view of the said attachment an Fig. 4 is a like view of a crucible with.

sprues attached over a wax pattern of the proposed denture.

The swinging machine is set up one baseplate 5, the pedestal 6 of same being 'se I cured to the plate. On the pedestal is a gear box 7 containing geared wheels and a handle 8 for rotating same. The wheels are geared to rotate the driven member about five (5) times faster than the driving wheel and on the driven wheel spindle9, that projects laterally from the gear box, the investment basket or stirrup 10 is hung. This spindle 9 is made to a loose fit in its bearing and no counterweight is provided to the basket 10. The base plate 5 is supported by bolts 11 on a plate 12 and is cushioned on springs 13' on the bolts.

The investmentcontaining the wax pattern 16 is held in the basket and heat is ap-.

plied to reduce the pattern and formthe mould. At the same time metal from which the denture is to be made is placed in the crucible 19 on the investment and which is in communication with the mould through, preferably, three sprue holes and the connections. molten condition and the handle is then turned to rotate the basket about the spindle 9. When this occurs a centrifugal force is set up that tends to transfer the metal from the crucible through the sprues to the heatedmould,-but at the same time, owing to the unstable mounting of the pedestal 6 and the absence of any counterweight, lateral oscillatory movements will be imparted to the.

basket. These lateral movements will tend to retard the centrifugal force and assist inthe more even and gentle distribution of the metal within the mould, thus avoiding damage to the walls of the same. a

In Fig. 4 the crucible is shown over the pattern with the connectin sprues between the s rue holes thereinan t e mould. It will understood that the whole arrangement will have been properly invested with a suitable material, leaving; only the opening in the crucible uncovered, before placin the This metal is reduced by heat to a sprue ipe 14 is cemented. The crucible is i partial y roofed in and on the edge of'the partial roof near the opening is a downwardly depending flange 15. If the handle be turned m a direction to cause the investment basket to move towards the o erator the molten metal will be forced up t e side of the crucible against the roof and the deending flange and will by the latter be deected downwards over the sprues.

It is very' important that 'the' handle be turned in the right direction while" the molten metal is in the crucible otherwise it will be spilled and to avoid this happenin a means 15 provided for stopping the han e being reversed. This consists of a slotted plate 17 on one end of which is a hinged stop member 18. This slotted plate is placed over and secured to a stud on' the gear box 7, of which there may be several as desired, with the sto 18 near the handle that is thus prevented y the stop from being turned in the wrong direction. When however the handle is turned correctly, it will after completing one revolution, come against the hinged member that will fall over and then lie flat on the plate 17. This the preferred form of stop recommended for use in this machine.

The spindle 9 is kept loose in its bearing to assist in promoting instabilit' in the machine but instead of the spin le being of lesser diameter than its bearing and parallel therewith it may taper therein, being 0 maximum diameter at its inner end. At its outer end the basket sleeve mountin is secured to the spindle which will be disposed to knock about in its bearing when the uncounterweighted basket is rotated, thereby assisting in attaining the object this invention has in view, namely, to impart to the investment while being swung the necessa lateral oscillatory movements, as explaine Having now described my invention what' I claim as new and desire to secure by Letters Patent is 1. In a machine for castin dentures in metal, an unstable standar and means thereon for rotating aninvestm ent containing a mold and molten metal, said means comprising a horizontal spindle on the standard and a rod on the spindle from which the investment is-suspended and to which it is rigidly attached.

2.-In machines for casting dentures in metal, an unstable baseplate, a pedestal thereon, a gearbox on the pedestal, a rotatable spindle extending laterally from the box and an investment basket having no counterweight secured to and suspended from the rotatable. s indle.

3. In machines or casting dentures in metal, a pedestal, a gear box thereon, a rotatable spindle extending laterally from the gear box, an investment basket having no counterweight secured to and suspended from the rotatable spindle, an unstable baseplate to the pedestal, bolts that retain the baseplate in position and cushion springs on the bolts below the plate and on which it seats.

4. In machines for casting dentures in metal, an unstable baseplate, a pedestal thereon, a gear box on the pedestal, a rotatable spindle made to a loose fit in its bearing extending laterally from the gear box f and an investment basket havin no counterweight secured to and suspen ed from the rotatable spindle.

5. In machines for casting dentures in metal, an unstable baseplate, a pedestal thereon, a gear box on the pedestal, a rotatable spindle made to alloose fit in its bearin extending laterall from the gear box and an uncounterweig ted investment basket secured to and suspended from the rotatable spindle.

In testimon whereof I aflix my signature.

REDERICK WM. NUNN 

